Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Jan. 31, 2015	Jul. 31, 2014
Assets
Contract receivables, allowance for doubtful accounts and contract adjustments	$ 5,966,241	$ 6,126,854
Property, building and equipment, accumulated depreciation	$ 24,674,231	$ 28,615,915
Shareholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	2,000,000us-gaap_PreferredStockSharesAuthorized	2,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, issued (in shares)	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Class A [Member]
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	6,000,000	6,000,000
Common stock, issued (in shares)	2,699,727	2,699,727
Treasury stock (in shares)	40,553	40,553
Class B [Member]
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	10,000,000	10,000,000
Common stock, issued (in shares)	1,693,998	1,693,998
Treasury stock (in shares)	64,801	64,801

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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